This core will supply large scale amount of eukaryotic and prokaryotic expression system-produced proteins. Specifically, CD4/1-183 and gp41 will be made in T7-based E. coli expression systems as inclusion bodies. In addition, Lec3.2.8.1 generated ADA and SF2 HIV-gp120 and gp160 proteins will be produced. Large scale mAb production will also be the responsibility of this core. As required, selenomethionine labeling of eukaryotically expressed protein will be undertaken for x-ray crystallography as well as /15N labeling of E. coli produced proteins for NMR analysis. Large scale mini-protein will be performed by this core once appropriate constructs have been generated. The assay component of the core will test small molecules identified by SAR by NMR as binders to CD4, gp120 or gp41 for their functional effects on CD4-gp120 interaction, HIV viral infectivity and for class II MHC interaction using a set of nine assays as detailed in the following section.